Derivatives and Hedging - Netting Arrangement (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Derivative Asset [Abstract]
Derivative assets, total derivatives subject to a master netting arrangement, gross amounts recognized		$ 191,061	$ 225,227
Derivative assets, total derivative subject to a master netting arrangement, gross amounts offset in the Consolidated Balance Sheets		0	0
Derivative assets, total derivatives subject to a master netting arrangement, net amount presented in the consolidated balance sheets		191,061	225,227
Derivative assets, total derivatives subject to a master netting arrangement, gross amounts not offset in the consolidated balance sheet, financial instruments	[1]	0	0
Derivate assets, total derivatives subject to a master netting arrangement, gross amounts not offset in the consolidated balance sheets, cash collateral received/pledged	[1]	33,517	58,309
Derivative assets, total derivatives subject to master netting arrangements, net amount		157,544	166,918
Derivative assets, total derivatives not subject to a master netting arrangement		265,042	260,736
Derivative assets, total derivatives not subject to a master netting arrangement, net amount		265,042	260,736
Total derivative financial assets, gross amounts recognized		456,103	485,963
Total derivative financial assets, net amount presented in the consolidated balance sheet		456,103	485,963
Total derivative financial assets, net amount		422,586	427,654
Derivative Liability [Abstract]
Derivative liabilities, total derivative subject to a master netting arrangement, gross amounts recognized		269,255	259,018
Derivative liabilities, total derivative subject to a master netting arrangement, gross amount offset in the consolidated balance sheets		0	0
Derivative liabilities, total derivative subject to a master netting arrangement, net amount presented in the consolidated balance sheets		269,255	259,018
Derivative liabilities, total derivative subject to a master netting arrangement, gross amounts not offset in the consolidated balance sheets, financial instruments	[1]	23,856	29,677
Derivative liabilities, total derivative subject to a master netting arrangement, gross amounts not offset in the consolidated balance sheets, cash collateral received/pledged	[1]	159,594	44,163
Derivative liabilities, total derivative subject to a master netting arrangement, net amount		85,805	185,178
Derivative Liability, Not Subject to Master Netting Arrangement		72,692	103,240
Derivative Liability, Not Subject to Master Netting Arrangement Deduction		72,692	103,240
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement		341,947	362,258
Total derivative financial liabilities, net amount presented in the consolidated balance sheets		341,947	362,258
Total derivative financial liabilities, net amount		$ 158,497	$ 288,418

[1] The actual amount of collateral received/pledged is limited to the asset/liability balance and does not include excess collateral received/pledged. When excess collateral exists the collateral shown in the table above has been allocated based on the percentage of the actual amount of collateral posted.